April 2011 Fukushima earthquake

Fukushima Hamadōri earthquake

UTC time	2011-04-11 08:16:12
ISC event	16416735
USGS-ANSS	ComCat
Local date	11 April 2011
Local time	17:16 JST
Magnitude	6.6 Mw[1]
Depth	13 km (8 mi)
Epicenter	37°00′04″N 140°24′04″E / 37.001°N 140.401°E / 37.001; 140.401[1]
Type	Dip-slip
Areas affected	Japan
Max. intensity	MMI VIII (Severe) JMA 6−
Peak acceleration	2.11 g 2071.7 Gal
Tsunami	No
Landslides	Yes
Casualties	4 dead, 10 injured

A potent magnitude 6.6 M_w intraplate aftershock occurred at 17:16 JST (08:16 UTC) on 11 April, in the Hamadōri region of Fukushima, Japan. With a shallow focus of 13 km (8.1 mi), the earthquake was centred inland about 36 km (22 mi) west of Iwaki, causing widespread strong to locally severe shaking. It was one of many aftershocks to follow the 11 March Tōhoku earthquake, and the strongest to have its epicentre located inland.

The earthquake occurred as a result of normal faulting to the west of Iwaki, and triggered numerous landslides across adjacent mountainous areas. A few fires broke out, and 220,000 households lost electricity. Officials issued localised tsunami alerts, though no significant waves were generated. The earthquake caused little structural damage, but killed four people and injured ten others. The strong ground movements triggered the reactivation of a nearby geological fault, prompting researchers to conduct extensive surveys in the region.